Dr. DiPietro's goal is to perform independent research in the field of immunology as it relates to the oral cavity and mucosal immune system. The specific research proposal involves an investigation of the genes which encode the variable portion of the heavy chains of immunoglobulins in rabbit. The research of Phase I is intended to determine the contribution of the number of VH genes to the generation antibody diversity. Using recombinant DNA techniques, a series of cosmid clones which represent the entire VH encoding region of the rabbit will be identified and isolated from a rabbit genomic library. The VH genes will be enumerated and subgroups identified by means of subgroup specific probes. During Phase II, the regulation of expression of the VH genes will be studied. Selected VH genes will be subcloned into appropriate expression vectors and their level of expressibility determined. VH genes of different expressibility will be compared at the DNA level in order to determine the reasons for any differences.